Land https://codereview.chromium.org/889083003/ to update libsrtp to upstream 1.5.0

srtp/test/rtp_decoder.c

+/*
+ * rtp_decoder.c
+ *
+ * decoder structures and functions for SRTP pcap decoder
+ *
+ * Example:
+ * $ wget --no-check-certificate https://raw.githubusercontent.com/gteissier/srtp-decrypt/master/marseillaise-srtp.pcap
+ * $ ./test/rtp_decoder -a -t 0 -e 128 -b aSBrbm93IGFsbCB5b3VyIGxpdHRsZSBzZWNyZXRz \
+ *    < ~/marseillaise-srtp.pcap | text2pcap -t "%M:%S." -u 10000,10000 - - > ./marseillaise-rtp.pcap
+ *
+ * Bernardo Torres <bernardo@torresautomacao.com.br>
+ *
+ * Some structure and code from https://github.com/gteissier/srtp-decrypt
+ */
+/*
+ *      
+ * Copyright (c) 2001-2006 Cisco Systems, Inc.
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 
+ *   Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * 
+ *   Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ * 
+ *   Neither the name of the Cisco Systems, Inc. nor the names of its
+ *   contributors may be used to endorse or promote products derived
+ *   from this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+#include "getopt_s.h"       /* for local getopt()  */
+#include <assert.h>         /* for assert()  */
+
+#include <pcap.h>
+#include "rtp_decoder.h"
+
+#define MAX_KEY_LEN      96
+#define MAX_FILTER 256
+
+int
+main (int argc, char *argv[]) {
+  char errbuf[PCAP_ERRBUF_SIZE];
+  bpf_u_int32 pcap_net = 0;
+  pcap_t *pcap_handle;
+#if BEW
+  struct sockaddr_in local;
+#endif 
+  sec_serv_t sec_servs = sec_serv_none;
+  int c;
+  int key_size = 128;
+  int tag_size = 8;
+  int gcm_on = 0;
+  char *input_key = NULL;
+  int b64_input = 0;
+  char key[MAX_KEY_LEN];
+  struct bpf_program fp;
+  char filter_exp[MAX_FILTER] = "";
+  rtp_decoder_t dec;
+  srtp_policy_t policy;
+  err_status_t status;
+  int len;
+  int expected_len;
+  int do_list_mods = 0;
+
+  fprintf(stderr, "Using %s [0x%x]\n", srtp_get_version_string(), srtp_get_version());
+
+  /* initialize srtp library */
+  status = srtp_init();
+  if (status) {
+    fprintf(stderr, "error: srtp initialization failed with error code %d\n", status);
+    exit(1);
+  }
+
+  /* check args */
+  while (1) {
+    c = getopt_s(argc, argv, "b:k:gt:ae:ld:f:");
+    if (c == -1) {
+      break;
+    }
+    switch (c) {
+        case 'b':
+      b64_input = 1;
+      /* fall thru */
+    case 'k':
+      input_key = optarg_s;
+      break;
+    case 'e':
+      key_size = atoi(optarg_s);
+      if (key_size != 128 && key_size != 256) {
+        fprintf(stderr, "error: encryption key size must be 128 or 256 (%d)\n", key_size);
+        exit(1);
+      }
+      input_key = malloc(key_size);
+      sec_servs |= sec_serv_conf;
+      break;
+    case 't':
+      tag_size = atoi(optarg_s);
+      if (tag_size != 8 && tag_size != 16) {
+        fprintf(stderr, "error: GCM tag size must be 8 or 16 (%d)\n", tag_size);
+        //exit(1);
+      }
+      break;
+    case 'a':
+      sec_servs |= sec_serv_auth;
+      break;
+    case 'g':
+      gcm_on = 1;
+      sec_servs |= sec_serv_auth;
+      break;
+    case 'd':
+      status = crypto_kernel_set_debug_module(optarg_s, 1);
+      if (status) {
+        fprintf(stderr, "error: set debug module (%s) failed\n", optarg_s);
+        exit(1);
+      }
+      break;
+    case 'f':
+      if(strlen(optarg_s) > MAX_FILTER){
+        fprintf(stderr, "error: filter bigger than %d characters\n", MAX_FILTER);
+        exit(1);
+      }
+      fprintf(stderr, "Setting filter as %s\n", optarg_s);
+      strcpy(filter_exp, optarg_s);
+      break;
+    case 'l':
+      do_list_mods = 1;
+      break;
+    default:
+      usage(argv[0]);
+    }
+  }
+
+  if (do_list_mods) {
+    status = crypto_kernel_list_debug_modules();
+    if (status) {
+      fprintf(stderr, "error: list of debug modules failed\n");
+          exit(1);
+    }
+    return 0;
+  }
+   
+  if ((sec_servs && !input_key) || (!sec_servs && input_key)) {
+    /* 
+     * a key must be provided if and only if security services have
+     * been requested 
+     */
+          if(input_key == NULL){
+                  fprintf(stderr, "key not provided\n");
+          }
+          if(!sec_servs){
+                  fprintf(stderr, "no secservs\n");
+          }
+    fprintf(stderr, "provided\n");
+    usage(argv[0]);
+  }
+   
+
+
+  /* report security services selected on the command line */
+  fprintf(stderr, "security services: ");
+  if (sec_servs & sec_serv_conf)
+    fprintf(stderr, "confidentiality ");
+  if (sec_servs & sec_serv_auth)
+    fprintf(stderr, "message authentication");
+  if (sec_servs == sec_serv_none)
+    fprintf(stderr, "none");
+  fprintf(stderr, "\n");
+  
+  /* set up the srtp policy and master key */    
+  if (sec_servs) {
+    /* 
+     * create policy structure, using the default mechanisms but 
+     * with only the security services requested on the command line,
+     * using the right SSRC value
+     */
+    switch (sec_servs) {
+    case sec_serv_conf_and_auth:
+      if (gcm_on) {
+#ifdef OPENSSL
+        switch (key_size) {
+        case 128:
+          crypto_policy_set_aes_gcm_128_8_auth(&policy.rtp);
+          crypto_policy_set_aes_gcm_128_8_auth(&policy.rtcp);
+          break;
+        case 256:
+          crypto_policy_set_aes_gcm_256_8_auth(&policy.rtp);
+          crypto_policy_set_aes_gcm_256_8_auth(&policy.rtcp);
+          break;
+        }
+#else
+        fprintf(stderr, "error: GCM mode only supported when using the OpenSSL crypto engine.\n");
+        return 0;
+#endif
+      } else {
+        switch (key_size) {
+        case 128:
+          crypto_policy_set_rtp_default(&policy.rtp);
+          crypto_policy_set_rtcp_default(&policy.rtcp);
+          break;
+        case 256:
+          crypto_policy_set_aes_cm_256_hmac_sha1_80(&policy.rtp);
+          crypto_policy_set_rtcp_default(&policy.rtcp);
+          break;
+        }
+      }
+      break;
+    case sec_serv_conf:
+      if (gcm_on) {
+          fprintf(stderr, "error: GCM mode must always be used with auth enabled\n");
+          return -1;
+      } else {
+        switch (key_size) {
+        case 128:
+          crypto_policy_set_aes_cm_128_null_auth(&policy.rtp);
+          crypto_policy_set_rtcp_default(&policy.rtcp);      
+          break;
+        case 256:
+          crypto_policy_set_aes_cm_256_null_auth(&policy.rtp);
+          crypto_policy_set_rtcp_default(&policy.rtcp);      
+          break;
+        }
+      }
+      break;
+    case sec_serv_auth:
+      if (gcm_on) {
+#ifdef OPENSSL
+        switch (key_size) {
+        case 128:
+          crypto_policy_set_aes_gcm_128_8_only_auth(&policy.rtp);
+          crypto_policy_set_aes_gcm_128_8_only_auth(&policy.rtcp);
+          break;
+        case 256:
+          crypto_policy_set_aes_gcm_256_8_only_auth(&policy.rtp);
+          crypto_policy_set_aes_gcm_256_8_only_auth(&policy.rtcp);
+          break;
+        }
+#else
+        printf("error: GCM mode only supported when using the OpenSSL crypto engine.\n");
+        return 0;
+#endif
+      } else {
+        crypto_policy_set_null_cipher_hmac_sha1_80(&policy.rtp);
+        crypto_policy_set_rtcp_default(&policy.rtcp);
+      }
+      break;
+    default:
+      fprintf(stderr, "error: unknown security service requested\n");
+      return -1;
+    } 
+
+    policy.key  = (uint8_t *) key;
+    policy.ekt  = NULL;
+    policy.next = NULL;
+    policy.window_size = 128;
+    policy.allow_repeat_tx = 0;
+    policy.rtp.sec_serv = sec_servs;
+    policy.rtcp.sec_serv = sec_servs; //sec_serv_none;  /* we don't do RTCP anyway */
+      fprintf(stderr, "setting tag len %d\n", tag_size);
+policy.rtp.auth_tag_len = tag_size;
+  
+    if (gcm_on && tag_size != 8) {
+      fprintf(stderr, "setted tag len %d\n", tag_size);
+        policy.rtp.auth_tag_len = tag_size;
+    }
+
+    /*
+     * read key from hexadecimal or base64 on command line into an octet string
+     */
+    if (b64_input) {
+      int pad;
+      expected_len = policy.rtp.cipher_key_len*4/3;
+      len = base64_string_to_octet_string(key, &pad, input_key, expected_len);
+      if (pad != 0) {
+        fprintf(stderr, "error: padding in base64 unexpected\n");
+        exit(1);
+      }
+    } else {
+      expected_len = policy.rtp.cipher_key_len*2;
+      len = hex_string_to_octet_string(key, input_key, expected_len);
+    }
+    /* check that hex string is the right length */
+    if (len < expected_len) {
+      fprintf(stderr, 
+              "error: too few digits in key/salt "
+              "(should be %d digits, found %d)\n",
+              expected_len, len);
+      exit(1);    
+    } 
+    if (strlen(input_key) > policy.rtp.cipher_key_len*2) {
+      fprintf(stderr, 
+              "error: too many digits in key/salt "
+              "(should be %d hexadecimal digits, found %u)\n",
+              policy.rtp.cipher_key_len*2, (unsigned)strlen(input_key));
+      exit(1);    
+    }
+    
+    fprintf(stderr, "set master key/salt to %s/", octet_string_hex_string(key, 16));
+    fprintf(stderr, "%s\n", octet_string_hex_string(key+16, 14));
+  
+  } else {
+    /*
+     * we're not providing security services, so set the policy to the
+     * null policy
+     *
+     * Note that this policy does not conform to the SRTP
+     * specification, since RTCP authentication is required.  However,
+     * the effect of this policy is to turn off SRTP, so that this
+     * application is now a vanilla-flavored RTP application.
+     */
+    policy.key                 = (uint8_t *)key;
+    policy.ssrc.type           = ssrc_specific;
+    policy.rtp.cipher_type     = NULL_CIPHER;
+    policy.rtp.cipher_key_len  = 0; 
+    policy.rtp.auth_type       = NULL_AUTH;
+    policy.rtp.auth_key_len    = 0;
+    policy.rtp.auth_tag_len    = 0;
+    policy.rtp.sec_serv        = sec_serv_none;   
+    policy.rtcp.cipher_type    = NULL_CIPHER;
+    policy.rtcp.cipher_key_len = 0; 
+    policy.rtcp.auth_type      = NULL_AUTH;
+    policy.rtcp.auth_key_len   = 0;
+    policy.rtcp.auth_tag_len   = 0;
+    policy.rtcp.sec_serv       = sec_serv_none;   
+    policy.window_size         = 0;
+    policy.allow_repeat_tx     = 0;
+    policy.ekt                 = NULL;
+    policy.next                = NULL;
+  }
+
+        pcap_handle = pcap_open_offline("-", errbuf);
+
+        if (!pcap_handle) {
+            fprintf(stderr, "libpcap failed to open file '%s'\n", errbuf);
+            exit(1);
+        }
+        assert(pcap_handle != NULL);
+        if ((pcap_compile(pcap_handle, &fp, filter_exp, 1, pcap_net)) == -1){
+            fprintf(stderr, "Couldn't parse filter %s: %s\n", filter_exp,
+                pcap_geterr(pcap_handle));
+            return (2);
+        }
+        if (pcap_setfilter(pcap_handle, &fp) == -1){
+          fprintf(stderr, "couldn't install filter %s: %s\n", filter_exp,
+              pcap_geterr(pcap_handle));
+          return (2);
+        }
+        dec = rtp_decoder_alloc();
+        if (dec == NULL) {
+          fprintf(stderr, "error: malloc() failed\n");
+          exit(1);
+        }
+        fprintf(stderr, "Starting decoder\n");
+        rtp_decoder_init(dec, policy);
+
+        pcap_loop(pcap_handle, 0, rtp_decoder_handle_pkt, (u_char *)dec);
+
+        rtp_decoder_deinit_srtp(dec);
+        rtp_decoder_dealloc(dec);
+
+  status = srtp_shutdown();
+  if (status) {
+    fprintf(stderr, "error: srtp shutdown failed with error code %d\n", status);
+    exit(1);
+  }
+
+  return 0;
+}
+
+
+void
+usage(char *string) {
+
+  fprintf(stderr, "usage: %s [-d <debug>]* [[-k][-b] <key> [-a][-e]]\n"
+         "or     %s -l\n"
+         "where  -a use message authentication\n"
+         "       -e <key size> use encryption (use 128 or 256 for key size)\n"
+         "       -g Use AES-GCM mode (must be used with -e)\n"
+         "       -t <tag size> Tag size to use in GCM mode (use 8 or 16)\n"
+         "       -k <key>  sets the srtp master key given in hexadecimal\n"
+         "       -b <key>  sets the srtp master key given in base64\n"
+         "       -l list debug modules\n"
+         "       -f \"<pcap filter>\" to filter only the desired SRTP packets\n"
+         "       -d <debug> turn on debugging for module <debug>\n",
+         string, string);
+  exit(1);
+  
+}
+
+rtp_decoder_t
+rtp_decoder_alloc(void) {
+  return (rtp_decoder_t)malloc(sizeof(rtp_decoder_ctx_t));
+}
+
+void
+rtp_decoder_dealloc(rtp_decoder_t rtp_ctx) {
+  free(rtp_ctx);
+}
+
+err_status_t
+rtp_decoder_init_srtp(rtp_decoder_t decoder, unsigned int ssrc) {
+  decoder->policy.ssrc.value = htonl(ssrc);
+  return srtp_create(&decoder->srtp_ctx, &decoder->policy);
+}
+
+int
+rtp_decoder_deinit_srtp(rtp_decoder_t decoder) {
+  return srtp_dealloc(decoder->srtp_ctx);
+}
+
+int
+rtp_decoder_init(rtp_decoder_t dcdr, srtp_policy_t policy){
+        dcdr->rtp_offset = DEFAULT_RTP_OFFSET;
+        dcdr->srtp_ctx = NULL;
+        dcdr->start_tv.tv_usec = 0;
+        dcdr->start_tv.tv_sec = 0;
+        dcdr->frame_nr = -1;
+    dcdr->policy = policy;
+        dcdr->policy.ssrc.type  = ssrc_specific;
+        return 0;
+}
+
+/* 
+ * decodes key as base64
+ */
+
+void hexdump(const void *ptr, size_t size) {
+  int i, j;
+  const unsigned char *cptr = ptr;
+
+  for (i = 0; i < size; i += 16) {
+    fprintf(stdout, "%04x ", i);
+    for (j = 0; j < 16 && i+j < size; j++) {
+      fprintf(stdout, "%02x ", cptr[i+j]);
+    }
+    fprintf(stdout, "\n");
+  }
+}
+
+void
+rtp_decoder_handle_pkt(u_char *arg, const struct pcap_pkthdr *hdr,
+        const u_char *bytes){
+  rtp_decoder_t dcdr = (rtp_decoder_t)arg;
+  int pktsize;
+  struct timeval delta;
+  int octets_recvd;
+  err_status_t status;
+  dcdr->frame_nr++;
+
+  if (dcdr->start_tv.tv_sec == 0 && dcdr->start_tv.tv_sec == 0) {
+    dcdr->start_tv = hdr->ts;
+  }
+
+  if (hdr->caplen < dcdr->rtp_offset) {
+    return;
+  }
+  const void *rtp_packet = bytes + dcdr->rtp_offset;
+
+  memcpy((void *)&dcdr->message, rtp_packet, hdr->caplen - dcdr->rtp_offset);
+  pktsize = hdr->caplen - dcdr->rtp_offset;
+  octets_recvd = pktsize;
+
+  if (octets_recvd == -1) {
+    return;
+  }
+
+  /* verify rtp header */
+  if (dcdr->message.header.version != 2) {
+    return; //return -1;
+  }
+  if(dcdr->srtp_ctx == NULL){
+    status = rtp_decoder_init_srtp(dcdr, dcdr->message.header.ssrc);
+    if (status) {
+      exit(1);
+    }
+ }
+  if(dcdr->srtp_ctx != NULL){
+  }
+  status = srtp_unprotect(dcdr->srtp_ctx, &dcdr->message, &octets_recvd);
+  if (status){
+    return;
+  }
+  timersub(&hdr->ts, &dcdr->start_tv, &delta);
+  fprintf(stdout, "%02ld:%02ld.%06lu\n", delta.tv_sec/60, delta.tv_sec%60, delta.tv_usec);
+  hexdump(&dcdr->message, pktsize);
+}
+
+void rtp_print_error(err_status_t status, char *message){
+    fprintf(stderr,
+            "error: %s %d%s\n", message, status,
+            status == err_status_replay_fail ? " (replay check failed)" :
+            status == err_status_bad_param ? " (bad param)" :
+            status == err_status_no_ctx ? " (no context)" :
+            status == err_status_cipher_fail ? " (cipher failed)" :
+            status == err_status_key_expired ? " (key expired)" :
+            status == err_status_auth_fail ? " (auth check failed)" : "");
+}